This invention relates to a method for continuously emulsifying organopolysiloxane gums. More particularly, this invention relates to a method that is capable of the continuous emulsification of organopolysiloxane gums that have been difficult to emulsify due to their very high degrees of polymerization.
Emulsions of organopolysiloxanes are widely used in industry as lubricants, release agents including mold-release agents, fiber-treatment agents, glass fiber-treatment agents, cosmetic bases, lustrants, and paint additives. These organopolysiloxane emulsions are prepared by mixing an emulsifying agent and water into a starting fluid organopolysiloxane gum. However, conversion into an emulsion can be a problem as the viscosity of the organopolysiloxane rises, resulting in a corresponding increasing difficulty of emulsification.
Japanese Patent Publication Number Sho 59-51565 51,565/1984! proposes a method for emulsification of such high-viscosity organopolysiloxanes. This method uses a cylindrical container, and installed therein, a mixing element comprising at least 3 disks placed at fixed intervals on a rotating shaft. Shearing and stirring are conducted by rotation of the mixing element. However, the use of at least 3 disks in this method installed on the rotating shaft coaxially and with a narrow interposed gap, limits the viscosity of organopolysiloxanes that can be mixed across these closely spaced disks, to at most about 70,000 centistokes. It is not practical to emulsify organopolysiloxanes with higher viscosities using this method.